Inorganic resin compositions, their preparation and use thereof

ABSTRACT

PCT No. PCT/BE95/00106 Sec. 371 Date Jul. 10, 1998 Sec. 102(e) Date Jul. 10, 1998 PCT Filed Nov. 17, 1995 PCT Pub. No. WO97/19033 PCT Pub. Date May 29, 1997Inorganic resin compositions comprising, in combination, an aqueous solution of metal phosphate, an oxy-boron compound, a wollastonite compound and other optional additives, inorganic composite articles and products reinforced by fillers and fibers including glass fibers obtained from these compositions and processes for preparing said products.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to inorganic resins in composition of aqueoussolution of inorganic metal phosphate, oxy-boron compound andwollastonite compound; to various additives for said composition; toprocesses for forming said resin and the resin product; to productsmanufactured by said resin composition and said process. The uniquefeather of this invention is that pot life of the fresh resin andtemperature increase of the resin during setting reaction can becontrolled so that its pot life can be between few minutes to an orderof magnitude of several hours or longer; whereas hardened resin andresin product have good material properties and wide range of use. Bothcellular and non cellular structures can be obtained.

The resin of the present invention can be used as adhesives and binders.In terms or properties, inorganic resin of the present invention and itsproducts lies between those such as e.g. Portland cement and those suchas e.g. technical ceramics. Fresh mixture or the resin has lowviscosity, is storable at low temperatures and easy to use; while thehardened resin is strong, durable, resistant against mild acid attack,fire-proof, and stable at high temperatures. It is suitable to make,such as but not limited, adhesives, binders, coatings and inorganiccomposites reinforced by fillers and fibres including all glass fibres,used both at low and high temperatures.

2. Description of the Related Art

Wollastonite has been employed not long time ago as primary material inphosphate cement compositions. Only few formulations are known in thatfield so far, they all have quick setting characteristics. Hardening ofthese compositions usually occurs at ambient condition in a range fromseveral minutes to ca 10-20 minutes after forming of the cement, whichis practically-impossible to be used in applications such as that ofcomposite materials. Large amount of heat production is another typicalphenomenon of the traditional phosphate cements which may producedefects inside of the material and affects negatively on materialproperties. When wollastonite is employed as primary material in thecomposition, the quick setting may result in extra voids and cracks instructure of the material due to formation of CO₂ during the settingprocess produced by decomposition of calcite (CaCO₃) contained in thewollastonite, which further undermines strength and durability of thematerial. U.S. Pat. No. 3,804,651 dated Apr. 16, 1974 to C. E. Semlerdiscloses a quick setting gel binder of phosphate solutions andwollastonite. The cured binder shows a good mechanical strength anddurability, but its fresh mixture gels quickly and is claimed as a quicksetting composition. U.S. Pat. No. 4,375,516 dated Mar. 1, 1983 toJeffery L., Barrall et.al discloses a material in composition ofaluminium phosphate solution and solid component containingwollastonite. This composition usually sets in several minutes in thetemperature range of 4-25° C. U.S. Pat. No. 4,792,359 dated Dec. 20,1988 to Jeffery L., Barrall et.al discloses a method to preparecomposite materials by hot pressing the mixture of phosphate cement andvaries fibres at about 85° C. under pressures, which takes advantage ofthe quick setting.

As a summary, these inorganic phosphate compositions are found notrelated to this invention. In terms of composition, no oxy-boroncompound is used to extend pot life of these phosphate cementcompositions; in terms of setting time, all available compositions has aquick setting; in terms of pot life during which period the mixturekeeps flowable, no information is available probably due to the quicksetting; in terms of application, all available compositions is used forpurposes which needs quick setting.

The inorganic resins of the present invention have a controllable potlife and temperature increase in its fresh state; and have good materialproperties for the hardened resin, such as, e.g., good mechanicalstrength, durability, resistance against mild acid attack, high scratchhardness, non flammability, high temperature resistance, and goodadhesion with other materials such as fibres including glass fibres,

SUMMARY OF THE INVENTION

The inorganic resins of the present invention are formed basically byreactions between three components, either physically separated or mixedor in combination thereof. The component A is an aqueous solution ofmetal phosphate preferably selected from the group consisting ofaluminium phosphates, zirconium phosphates, magnesium phosphates, zincphosphates, calcium phosphates, iron phosphates, including derivativesand mixtures thereof. It should be understood that the term solution ofthe component A is used broadly herein to include aqueous reactionmixtures, and the term derivative of metal phosphates herein includesall types of phosphate such as polyphosphate and dihydrogen phosphate.The component B comprises oxy-boron compound including its hydrates. Thecomponent C comprises wollastonite compound. Fillers and fibresincluding glass fibres can be introduced to the inorganic resin of thisinvention to improve material properties. Cellular structures of theinorganic resin can be produced by employing foaming agents andsurfactants.

Being formed by contacting all ingredients together by way of such asintermixing, fresh resin of this invention has an adjustable pot life inthe range from several minutes to an order of magnitude of several hoursor longer, and correspondingly a setting time from few minutes toseveral hours or longer at ambient temperatures; has a controlledtemperature increase during setting reaction; while the hardened resinhas very good material properties. The composition of the presentinvention interacts and is able to set without the use of externallyapplied heat. These compositions and their unique characteristics suchas the extended pot life distinguish themselves from the othertraditional phosphate cements in the related field. Hardened resin ofthis invention has a three dimensional network structures. Due to thisnature, inorganic resins of the present invention are formulated to beessentially strong, durable, resistant against environmental attack suchas acid rain, non flammable, and stable at high temperatures.

Inorganic resin of this invention has good adhesion with fibres,meanwhile it shows no attack against fibres including glass fibres.Accordingly qualified inorganic composites can be produced by thisinvention. Products made by inorganic resin of this invention canreplace at least a portion of presently known products based on organicresins, traditional cements and ceramics in a wide range ofapplications, such as, fibre reinforced composite products; mouldedconfigurations in cellular and non-cellular structures; thermal,electrical and/or acoustical insulations; binders and adhesives;coatings and or surfacing agents; patching compositions and the like.Further, the use of inexpensive materials and easy processing comparedto that of typical organic resins or ceramics offers a number ofadvantages over many of the organic resins and ceramics destined forsimilar applications.

It is therefore one objective of the present invention to provide arange of inorganic resin compositions with the above mentioned feathersand advantages.

Another objective of the present invention is to provide processes toprepare these resin compositions and resin products, as well as the usethereof.

These and other objectives and advantages of the present invention willbecome apparent from, the detailed description given hereafter by way ofnon limiting examples.

DETAILED DESCRIPTION OF THE INVENTION

The inorganic resins of the present invention are formed basically byreactions between three components, either physically separated or mixedor in combination thereof. The component A is an aqueous solution ofmetal phosphate preferably selected from the group consisting ofaluminium phosphates, zirconium phosphates, magnesium phosphates, zincphosphates, calcium phosphates, iron phosphates, including derivativesand mixtures thereof. It should be understood that the term solution ofthe component A is used broadly herein to include aqueous reactionmixtures, and the term derivative of metal phosphates herein includesall types of phosphate such as polyphosphate and dihydrogen phosphate.The component B comprises oxy-boron compound including its hydrates. Thecomponent C comprises wollastonite compound including natural andsynthetic wollastonite, in calcined or non-calcined state. Fillers andfibres including glass fibres can be introduced to the inorganic resinof this invention to improve material properties. Cellular structures ofthe inorganic resin can be produced by employing foaming agents andsurfactants. Having homogeneously mixed, the said components interact ina controlled way so that designed pot life and setting time can beobtained. Setting process of said inorganic resin is in generalexothermic, but the temperature increase of the resin during thereaction can be controlled. Inorganic resin of this invention may set atambient temperatures to form a strong, durable monolithic mass withoutapplying external heat.

In accordance with this invention, the most important ingredient toprepare the component A is phosphoric acid aqueous solution includingbut not limited, e.g., ortho-phosphoric acid, pyro-phosphoric acid andpolyphosphoric acid, used either alone or in combination thereof.Phosphoric acid is commercially available, with the 85 percent by weightbeing the most common concentration for the ortho-phosphoric acid. Otherphosphorous based acids may also be satisfactory to practice the presentinvention, providing that the overall water content of the reactionsystem is not too high. As a general rule, the phosphoric acid will besuitable if it contains the phosphorous, expressed as P₂ O₅, in range of14 to 135 parts by weight with respect to 100 parts by weight ofwollastonite in the component C, with 24 to 86 parts by weight beingpreferred.

To practice the present invention, metal phosphate which is relativelyinsoluble in water is preferred to be used in the component A. It isfound that metal phosphate selected from the group consisting ofaluminium phosphates, zirconium phosphates, magnesium phosphates, zincphosphates, calcium phosphates, iron phosphates, including derivativesand mixtures thereof, is preferred. With respect to 100 parts by weightof wollastonite in the component C, suitable amount of equivalent metaloxide contained in the metal phosphate, i.e., aluminium oxide, zirconiumoxide, magnesium oxide, zinc oxide, calcium oxide and iron oxide, is inthe range of 2 to 65 parts by weight, with 5 to 47 parts by weight beingpreferred.

In accordance with this invention, the amount of water employed in thecomponent A should be carefully controlled. Excessive water can convertthe resin into a thin mixture that will cause sedimentation of solidparticles such as the wollastonite, which leads to an inferior product.Insufficient water will not wet the dry particles adequately to allowthe necessary chemical reaction. The amount of water influences onconcentration of the reactive components and consequently affects on thepot life and setting process of the resin. The optimal amount of waterwill depend upon the very metal used in component A and the particularphysical characteristics of the constituents of dry particles of thisinvention, e.g., absorbency, surface area, etc. However, it must besufficient to adequately wet the dry particles, such as the wollastoniteand fillers and/or fibres, to form desirable mixture. This optimalamount of water can be determined on a blend by blend basis. Withrespect to 100 parts by weight of wollastonite in the component C, theamount of water used can range from about 8 to 150 parts by-weight, withfrom 11 to 95 parts by weight being preferred. The water content in thecomponent A should include, for purposes of calculation, any water ofhydration from the compounds in the component A, B and C.

In accordance with this invention, the component A can be basicallyprepared by mixing metal and/or metal oxide and/or metal phosphateincluding hydrates and derivatives thereof in phosphoric acid aqueoussolution at a temperature and for a time sufficient to form at least asemi-transparent solution. Sometimes only a particle-liquid suspensionis obtained after long time mixing due to such as impurities containedin the raw materials. A filtration process is then required to removethe undesolved portion of particles larger than 1 μm from the solution.The filtered solution can be employed to practise this invention if itcontains desired amount of said ingredients. A clear solutionhomogeneous in molecular level without discrete particle distribution ispreferred. It may be with or without color depends on the very metalemployed.

In general, the component A of this invention is a mixture composed ofvarious types of phosphate, including but not limited, i.e.orthophosphate, pyrophosphate, and polyphosphate, appeared either aloneor in combination thereof. Exact distribution of the different phosphatestructures depends on the method and raw materials employed to make thesolution, and on the age of the solution. However, a transparentsolution with an age of 3 months at 20° C. is found generally sufficientto practice this invention by any person skilled in the art. Thecomponent A can be prepared all together as one liquid, or preparedseparately and then mixed together as one liquid, or prepared separatelyand kept separately prior to use.

In accordance with this invention, the component B of this invention iscomposed of oxy-boron compound including its hydrates. The oxy-boroncompound actively participates into the setting reaction, results in thevery structure of the fresh resin of this invention with which the potlife can be controlled.

The oxy-boron compound used in this invention generally comprises theseboron compounds containing at least one boron-oxygen linkage, hereaftertermed the oxy-boron compound. The oxy-boron compound is found speciallyeffective in this invention in terms of producing a extended pot life,avoiding setting expansion and resin over-heating during the setting,i.e., temperature increases to more than 100° C. when free water in thecomposition boils. These compounds include, e.g., oxy acids of boronwhich contain one or more boron atoms such as, e.g., boric acid; saltsof such acids, such as the alkali metal and alkali earth metal saltsthereof, such as sodium borate, calcium borate and amine or ammoniumsalts thereof such as ammonium borate; and ester of such acids, such a;trialkoxy borate and triaryloxy borate, e.g., trimetal borate.Boron-containing starting materials which yield oxy-boron additives uponcontact with phosphate solutions of the component A can be used togenerate the oxy-boron compounds in situ. The preferred oxy-boroncompound include boric acid, the alkali metal and alkali earth salts ofthe boric acid such as the sodium borate, calcium borate including theirhydrates. The oxy-boron compound can be used as a dry powder or as asolution by dissolving them in water or phosphoric acids. The amount ofthe component B used in the composition of this invention can varyaccording to the degree of retardation and the temperature increasedesired. Generally, with respect to 100 parts by weight of wollastonitein the component C, the amount of the oxy-boron compound in the mixture,calculated on an anhydrous basis, ranging from about 0.2 to 50 parts byweight, preferably from about 2 to 20 parts by weight being suitable.

In accordance with this invention, the component C is the wollastonitecompound including natural and synthetic wollastonite, in calcined ornon-calcined state. Usually the commercially available wollastonite is amineral of natural calcium silicate (CaSiO₃) of acicular structure, witha theoretical composition of 48.3% CaO and 51.7% SiO₂ by weight. Thiswollastonite can be classified into two categories of low aspect ratioand high aspect ratio. The low aspect ratio wollastonite, commonly withaspect ratio of not higher than 10, including that of about 1, is mainlyused as flux and fillers in ceramic, metallurgical, construction andcoating application. The high aspect ratio wollastonite commonly withaspect ratio of 10-20 is used as fibres to produce effect ofreinforcement. The most important properties of the wollastonite thataffect behavior of the inorganic resin of the present invention aretheir loss on ignition (LOI), aspect ratio, granulometry, andwollastonite content. Those characteristics can change from onewollastonite to another, depends on its mineral origin, geologicalhistory and processing technique to obtain the wollastonite. Settingprocess of the inorganic resin of the present invention is in one way oranother influenced by origin of the wollastonite, which broadly includesfactors such as e.g. geological history, way of fabrication andimpurities of the wollastonite.

Loss on ignition of the wollastonite is due to release of CO₂ when thecalcite (CaCO₃), which is intimately associated with the wollastonite,is decomposed into CO₂ and CaO at high temperatures. To practise thisinvention, the less amount of associated calcite that can be achieved,the better the wollastonite will be. However, for a practical reason,certain amount of CaCO₃ content up to about 5 percent by weight ispresent in the commercially available wollastonite. High amount of thecalcite contained in the wollastonite is not desired, because it willproduce excessive CO₂ during mixing and reaction stage, which results ininternal defects and undermines mechanical strength. High calcitecontent of the wollastonite will also lead to a long mixing time inorder to achieve a homogeneous mixture thus increase difficult formaterial processing. High amount of the calcite present in thecomposition may disturb the three component reaction of this inventiondue to high reactivity between the calcite and the phosphate solution ofthe component A, which may lead to undesirable reactions and weakstructures. One way to completely eliminate the calcite is to heat thecommercial available wollastonite in a range of 550-1000° C. until thecalcite decomposes to CaO and CO₂. The calcination process seems toproduce no harmful effect on using the calcined wollastonite in thisinvention. To practice this invention, the range of the LOI valuebetween 20-1000° C. should not be more than 3 percent by weight. Using amixture of calcined and non-calcined wollastonite is preferred withwhich the LOI value can be completely controlled.

Granulometry of the wollastonite plays an important role in controllingpot life and setting time of the inorganic resins of the presentinvention. When the grain size is too small, the resin will be tooreactive and lead to a short pot life. However, when the grain size istoo large, only part of wollastonite is able to participate into thereaction so that the necessary constituent to form backbone of thestructure is insufficient. Coarse wollastonite will also cause theparticle sedimentation from the resin mixture due to its larger specificgravity (about 2.9). However, compared to traditional phosphate cement,this invention permits to use the wollastonite with relatively largergrain size due to the extended pot life, during which period thewollastonite will be decomposed to a satisfactory degree. To practicethis invention, the wollastonite used as primary reactant is preferrednot larger than 150 μm. The range of the particle size distribution isgiven in terms of having a product with preferred properties.Wollastonite with particle size larger than 150 μm may also be used inthe composition as reactive fillers and/or fibres to improve propertiesof the resin product.

According to the present invention, aspect ratio of the wollastoniteused as primary reactant should not be too high to avoid wollastonitefibre from entanglement during mixing which makes the mixing difficult.A preferable aspect ratio is not larger than about 10 which can producedesirable rheology and the wollastonite solubility in the solution ofmetal phosphate. Wollastonite content of the commercial wollastoniteproduct is preferred to be more than 90 percent by weight. Wollastonitewith aspect ratio of larger than about 10, and/or purity less than about90 percent by weight may be included in general as reactive fillersand/or fibres to reinforce the inorganic resin of the present invention.

In accordance with this invention, inorganic resins of the presentinvention can be packed and kept separately until prior the use in athree package system. However, a two package system is preferred whichcomprises a liquid phase and a solid phase. In accordance with thisinvention, the liquid phase may be composed of the component A and thecomponent B, the solid phase may be composed of the component C. Thewollastonite compound may also be partially mixed with the component A,or with the mixture of the component A and component B. The remainingportion of the wollastonite compound is kept separately until prior theuse. To practise this two package system, mixing of the component A andthe component B can be performed at a temperature and for a timesufficient to form an aqueous solution wherein the oxy-boron compoundsare dissolved and incorporated in said metal phosphate. Sometimes asolution with large particle suspension is obtained, then a filtrationprocess is required to remove particles larger than 1 μm from thesolution-provide that all necessary said components is present.

In accordance with this invention, setting process of the inorganicresin or present invention can be controlled by adjusting, such as,liquid/solid weight ratio, water content or the component A,granulometry of the wollastonite. The manner of changing theseparameters, whether alone or in combination may depend on variousfactors such as type of product desired and/or the type of equipmentutilised. In accordance with this invention, the setting process canalso be adjusted by curing temperatures. High temperatures will increasereactivity of the resin, shorten setting process and produce moreexothermic heat; on the other hand; low temperatures will reducereactivity of the resin and prolong the setting process. This provides alarge room for engineers to design and manufacture the composites basedon inorganic resin of this invention, which is not possible for thetraditional phosphate cements. It can be noted that the true scope andspirit of this invention is to provide a unique composition withcontrollable pot life for the fresh mixture and good material propertiesfor the hardened resin. This includes both quick setting and extendedsetting. The few minutes setting time allows for quick repairing work,while the extended pot life permits to make composite materials usingvarious available processing techniques.

In accordance with this invention, inorganic resin composition may befully cured at ambient temperatures within a limited duration. Forexample, at 20° C., the resin of this invention may be fully curedwithin 3 days in terms of developed strength and structural stability.Demoulding may however take place earlier, such as when the resinfinally sets. The resin can be cured in an open condition or closedcondition, or in combination thereof. Usually the resin shows nearly nosetting shrinkage when cured at ambient conditions, profile of anycomplicated configuration can be copied, and the resin products have agood surface finish. The cured resin has a good resistance against waterin terms of the dimension stability and chemical leaching, for instance,being immersed into water, pH value of the water keeps neutral, both theresin and the water is tasteless. Those properties are much similar tothat of organic polymer based resin, so that existing processingtechnique for organic and/or cement composite materials can be employedto make inorganic composite products based on this invention.

In principle, the resin products which are obtained do not require heatcuring and may be placed in boiling water without adverse effect. Theinorganic resin of the present invention can be placed in a desiredconfiguration, the components interact and harden into a monolithic bodywith a desired shape. However, curing and/or post curing at hightemperatures and high pressures might be recommended to convert theresin into the final structures, when the resin products are destinedfor use at high temperature and/or in high pressure conditions. Ingeneral, the post curing process can further improve material propertiesof the inorganic resin.

It is found that setting time of the fresh mixture of the presentinvention can be significantly prolonged at a temperature sufficientlylow to retard any setting reactions, so that the mixture remains viscousand/or gel like or as a slurry without setting. Being gradually heatedup, such as to ambient temperatures, the resin of this invention willresume its reactivity and set without negative effects on its materialproperties. A preferred method to practise this nature is to mix theresin composition and then keep the fresh mixture or slurry at the lowtemperatures. This nature provides a way to store the fresh resin forlater use, it reduces waste and makes the resin easy to handle. Bycontacting the wollastonite compound in the solution of phosphates withthe oxy-boron compound for a sufficiently long time, large solidparticles of the wollastonite may be decomposed, resulting in a slurrycontaining much smaller solid particles or even no discrete solidparticles. The inorganic resin as a slurry treated at a temperaturesufficient low to prevent any setting reaction may be used as a matrixmaterial to make a fibre reinforced composite or prepreg in which thefibres may be well impregnated. In practice, said slurry or said prepregis then brought on a surface capable of supporting said slurry or saidprepreg respectively, the slurry reacting to set as a shaped product ofthe inorganic resin or said prepreg.

It is observed that the inorganic resin of the present invention has avery good adhesion to other materials such as e.g., metals, organic andinorganic material such as the concrete based on the Portland cement. Ithas also good adhesion with fibres, such as, e.g., carbon fibres,organic fibres, such as e.g., polyester fibres, mineral fibres, such as,e.g., rockwool, metallic fibres and glass fibres, such as, e.g., E-glassfibres. The good adhesion between fibre and matrix is essential forcomposite materials to impasse the load from matrix to the fibre, thusincrease strength and stability of the composites. With theseadvantages, inorganic resins of this invention can be used to preparecomposite materials reinforced by fibres, such as, i.e., glass fibres.

Aggregate and refractory as long as they do not produce negative effecton material properties, preferably graded sand of mullite, silica, mica,cordierite, silicon carbide, can be included in the dry blend in acontrolled amount as filler to make the resin concrete of thisinvention, for improving performance and reducing cost of the resinproduct. Fillers can generally enhance the strength of the hardenedresin product. Filler usage may range up to about 90 percent by weightof the total composition. Other materials which can be used includeparticles of competent rocks or rock-forming minerals such as granite,basalt, dolomite, ansesite, feldspar, amphibole, pyroxene, olivine,gabbro, rhyolite, syenite, diorite, dolerite, peridotite, trachyte,obsidian, etc., as well as materials such as slag, fly ash of pulverisedcoal and that from corundum production, glass cullet, wood whips, andfibrous materials such as metal fibres, glass fibres, organic fibres andnatural fibres. When intended to be used at high temperatures,refractory fillers may employed, for instance, the refractory oxides,carbides, nitride, and silicides, such as aluminium oxide, lead oxide,chromic oxide, zirconium oxide or silicate, silica, silicon carbide,titanium nitride, molybdenum disilicide and carnonaceous material suchas graphite. In general, these fillers can be with different particlesize, and can be both with cellular and non-cellular structures.Mixtures of the fillers can be used, when desired, including mixtures ofmetals and the ceramics.

Characteristically, hardened resin concrete of this invention is strongand durable. Toughness of the resin product can be achieved by addingfibres. The resin product of present invention has a good resistanceagainst environmental attack, such as freezing (-20° C.)/thawing (20°C.) cycles in terms of mechanical strength and dimension stability ofthe resin product. The resin product of present invention has also agood resistance against acid attack, such as H₂ SO₄ solution of pH=1.5.Softening point of the inorganic resin itself is above 1100° C.

It is discovered that, surprisingly, articles based on the inorganicresin of the present invention has a very high surface scratch hardnesswhen abrasion resistant fillers, such as, silicon carbide, boroncarbide, corundum, garnet, emery, silica and mixtures thereof, are used.The surface scratch hardness for the resin itself is about 6 Moh in wetand dry condition, but it can be significantly increased to 8.5 Moh orhigher in dry condition, and 8 Moh or higher in wet condition when theabrasive grains are included in the inorganic resin composition.

In accordance with this invention, additives such as foaming agents andsurfactants can be added to the freshly mixed inorganic resin so thatshaped articles with cellular structures with different bulk densitiescan be produced. In general, carbonates are the suitable species toproduce uniform foaming of inorganic resin of this invention, althoughother foaming agents may also provide satisfactory results. Foaming iscaused by CO₂ decomposed from carbonates when contacting with acidicphosphate solutions. Carbonates such as MgCO₃, CaCO₃, ZnCO₃, Li₂ CO₃ andthe like, or mixture thereof, which produce relatively insolublephosphate can be used, with CaCO₃ and MgCO₃ being preferred. Othercarbonates such as Na₂ CO₃ and K₂ CO₃ which produce relatively solublephosphate salts may also be employed where leaching of the phosphatefrom the product in wet condition is not considered as a problem. Thefoaming agents can be added to the fresh resin of this invention at anymoment before setting, however, they can also be premixed with thecomponent C of this invention. Because the foaming is producedgradually, it is undesirable to have the setting prior to completefoaming. For that reason, this invention is very advantages overtraditional phosphate cements to produce cellular structures because ofthe extended setting. Furthermore, because of the extended pot life,this invention leaves sufficient time to place the fresh mixture of theinorganic resin into any complex mould configuration, so that a foamedresin product with good surface finish can be obtained.

In accordance with this invention, surfactant which is not affected byphosphoric acids may be added into the resin to promote cell stabilitywhen making cellular structures. The surfactant may be premixed with thecomponent C of this invention, or added to the freshly formed resinmixture before adding the foaming agent, so that the surfactant can bedistributed homogeneously over whole volume of the composition. Thesurfactant might be, such as, e.g., zinc stereate.

Various pigments, both organic and inorganic as far as their coloringeffect is not influenced by phosphoric acids and they have no negativeeffect on the inorganic resin of this invention, can be added to theresin to have colored resin products. The pigments can be used either aspowder or liquid or in combination thereof.

Generally, the inorganic resin of the present invention can be used as abinder both at low and high temperatures. In the field of compositematerials, due to the controlled pot life and setting process, fibrereinforced composite can be produced using available materialprocessing, such as, e.g., the hand lay-ups, the spray technique, theextrusion, the pultrusion and the hot pressing, wherein the resinimpregnates the fibres and/or fibre mats to form a fibre reinforcedproduct. The product based on inorganic resin of this invention can bestrong and tough due both to the resin and function of fibres. Theinvention is generally applicable as inorganic binder to prepare, likebut not limited, as coatings and/or surfacing agents such as e.g. fireresistance and corrosion resistance coatings; adhesives such as to bindmetals and/or woods; special cements and concretes, such as dentalmaterial, with various characteristics, e.g., high strength and lowleachate.

The inorganic resin of present invention can be applied indoors oroutdoors to concrete drives, storage yards, warehouse and factory floorsto repair and restore damaged surfaces. The resin can be used in thefield of roadway construction, roadway patches and building reparationor other load bearing purposes. The characteristics of any particularconcrete structures formed can depend on weight ratio of the variouscompounds, the nature of the aggregate employed, the curing conditionsas well as other factors. Due to good adhesion between the inorganicresin of this invention and other cement products, such as that based onthe Portland cement, the inorganic resin can be used to fill structurecracks in slabs, and repair highway median barrier walls. This resin canalso be used in situation requiring in general a quick, permanent repairof concrete. The resin can be used to make pipes, ducts, mouldedconfigurations in cellular and non-cellular structures; thermal,electrical and/or acoustical insulations; light weight products and thelike because of its moisture resistance, high dielectric properties andcellular structures.

The following experiments illustrate various embodiments of theinvention. The amounts of the various constituents are given in parts byweight. Other embodiments will be apparent to one of ordinary skill inthe art from a consideration of this specification or practice of theinvention described therein. It is intended that the specification andexperiments are considered as exemplary only, with the true scope andspirit of the invention being indicated by the claims which follow theexamples.

As an examplary, a basic resin composition without additives inaccordance with this invention is shown in Tab.1.

                  TABLE 1                                                         ______________________________________                                        Component A*                                                                             Component B     Component C                                        ______________________________________                                        Fe.sub.2 O.sub.3                                                                     0.7     Na.sub.2 B.sub.4 O.sub.7.10H.sub.2 O                                                       6.0  Wollasto-                                                                             70.0                                                                  nite                                         Al.sub.2 O.sub.3                                                                     4.3                       Calcined                                                                              30.0                                                                  wollasto-                                                                     nite                                         ZrO.sub.2                                                                            6.3                                                                    ZnO    13.1                                                                   P.sub.2 O.sub.5                                                                      55.3                                                                   H.sub.2 O                                                                            57.3                                                                   ______________________________________                                         *analytical result.                                                      

The component A, expressed by oxide according to oxide analysis, isprepared by dissolving Fe₂ O₃, Zr(OH)₄, granular reagent grade zincmetal, and aluminium pellets in extra pure quality, together withbalanced amount of water, in 85% orthophosphoric acid solution by mixingat about 90° C. until a clear solution is obtained. This solution iskept at an ambient temperature of about 20° C. for 6 months before use.The component B is Na₂ B₄ O₇.10H₂ O, commonly known as borax. It is adry powder with grain size less than 70 μm and in extra pure quality.The wollastonite of the component C has an aspect ratio of about 5, and99.5 percent by weight of the wollastonite is not more than about 70 μm.Part of the wollastonite is calcined at 800° C. and kept at 800° C. fora duration sufficient to get all CaCO₃ decomposed to CaO and CO₂.

In practice of this invention, the component A and component B arefirstly pre-mixed together by a mechanical mixer at about 90° C. forabout 24 hours to form an aqueous solution. The wollastonite andcalcined wollastonite in the component C are also pre-mixed, then addedto above mentioned solution and mixed by a planetary mixer at about 20°C. to form a fresh resin of this invention. The composition andprocedure to prepare the resin of this invention will be referred asbasic resin composition and basic preparation procedure hereafter.

EXAMPLE 1

Examples of controlled pot life and initial setting time are shown inTab.2.

                  TABLE 2                                                         ______________________________________                                        Component                                                                             Component B                   Initial                                 A       Na.sub.2 B.sub.4 O.sub.7.10H.sub.2 O                                                      Component C                                                                              Pot life*                                                                            set time                                ______________________________________                                        see Tab.1                                                                             0           see Tab.1   10 min.                                                                             20 min.                                 see Tab.1                                                                             2           see Tab.1   20 min.                                                                              1 hour                                 see Tab.1                                                                             4           see Tab.1   30 min.                                                                             10 hours                                see Tab.1                                                                             6           see Tab.1  2.5 hours                                                                            17 hours                                see Tab.1                                                                             10          see Tab.1    7 hours                                                                            24 hours                                ______________________________________                                         *the duration in which the resin keeps flowable                          

The fresh resin is formed by said basic resin composition and basicpreparation procedure. Curing of said resin is at an ambient temperatureof about 20° C. in a covered condition. The results shown in the Tab.2illustrate that pot life of the resin can be controlled so that bothquick setting and extended setting of the resin can be obtained byaddition of the component B. The pot life herein means the duration inwhich the fresh resin keeps flowable. The composition without the boraxhas a pot life of only 10 minutes which is too short to further addfillers or fibres, meanwhile the temperature of the mixture increases tomore than 100° C. during the reaction and it sets almost instantly. Onthe other hand, the resins of this invention induce less temperatureincrease and they are able to harden gradually. In general, morecomponent B is used, less temperature increase, more extended pot lifeand longer initial setting will be. Further more, inorganic resins ofthis invention have good surface finish.

EXAMPLE 2

The inorganic resin has said basic inorganic resin composition and ismade by said basic preparation procedure. This resin has a pot life ofabout 2.5 hours and initial setting of about 17 hours at 20° C. incovered condition. The resin gets slightly warm during setting processwith free water liberation but no noticeable setting shrinkage orexpansion. Being cured at 20° C. for 3 days in a covered condition, thespecimen is demoulded and subjected to further drying or wetting beforemechanical test. 3-points bending test shows that said resin has anaverage bending strength of 18.4 MPa, flexural modulus of 13.8 GPa whendried at 20° C. for 3 days; bending strength 12.3 MPa and flexuralmodulus 12.0 GPa when immersed into water at 20° C. for 3 days.

EXAMPLE 3

Two laminates are prepared by hand lay-ups. The matrix of the firstlaminate is the resin made from said basic resin composition and saidbasic preparation procedure, that of the second laminate is thepolyester. Each of the laminates is made with 4 layers of the sameunidirectional E-glass fibre mat. The laminates are cured at an ambienttemperature of ca 20° C. for 24 hrs in covered condition and then postcured at 60° C. for another 24 hours in uncovered condition.

                  TABLE 3                                                         ______________________________________                                                        Max     Max    Modulus E.sub.f V.sub.f                                V.sub.f strain  load   GPa     GPa                                    Matrix  vol %   %       N      measured                                                                              calculated                             ______________________________________                                        Inorganic                                                                             14.0    1.90    7388.9 10.2    10.6                                   resin*                                                                        Polyester                                                                             22.6    1.91    8659.4 17.8    17.2                                   ______________________________________                                         *Inorganic resin of this invention                                       

Results of tensile test are shown in the Tab.3, where the strain is amean value of the strain measured by strain gauge on both sides of thesamples; the V_(f) is the fibre volume fraction, E_(f) is the modulus ofthe glass fibre, The E_(f) V_(f) is calculated assuming E_(f) =76 GPa.It is observed that, for both laminates, their cracks are spreadeduniformly transversal to the fibre direction after the matrix break, andthere is no delamination occurred before final rupture of the fibres.

EXAMPLE 4

The resin has said basic composition and made by said basic preparationprocedure. The hardened resin is subjected to the freezing (-20°C.)/thawing (20° C.) cycles for 30 times, the sample shows no noticeabledimension change and cracks.

EXAMPLE 5

The resin has said basic composition and is made by said basicpreparation procedure. Additional 200 parts by weight of mullite of0-0.5 mm is added as filler. Curing is performed in a covered mould atan ambient temperature of 20° C. for 7 days, then demoulded and leftuncovered in the ambient condition for 3 days. Scratch hardness on cutsurface of the hardened resin is about 8.5, and there is no noticeablecrack or dimension change when immersed in H₂ SO₄ solution of pH=1.5during 14 days.

EXAMPLE 6

The resin has said basic composition and is made by said basicpreparation procedure. The fresh resin is made at an ambient temperatureof ca 20° C. and then left at -20° C. immediately. It remains flowablefor several days and then gradually evolves to a gel without setting at-20° C.

EXAMPLE 7

Composition of a foamed resin of this invention is shown in Tab.4, it ismade by said basic preparation procedure. The surfactant is zincstereate, the fibre is E-glass fibre. The MgCO₃ is added to the resinafter other ingredients being mixed. Mixture of this composition foamsgradually and sets at 20° C. without applying external heat. The foamedresin is strong and it has a bulk density of about 350 kg/m³ and hasuniform cell structures.

                  TABLE 4                                                         ______________________________________                                        Component A*                                                                           Component B Component C Additives                                    ______________________________________                                        Fe.sub.2 O.sub.3                                                                    0.7    Na.sub.2 B.sub.4 O.sub.7                                                                2.0 Wollasto-                                                                            100.0                                                                              MgCO.sub.3                                                                           5.0                                          .10H.sub.2 O  nite                                               Al.sub.2 O.sub.3                                                                    4.3                              Surfac-                                                                              1.0                                                                    tant                                   ZrO.sub.2                                                                           6.3                              Talc   10.0                            ZnO   13.1                             Fibre  0.5                             P.sub.2 O.sub.5                                                                     55.3                                                                    H.sub.2 O                                                                           57.3                                                                    ______________________________________                                         *analytical result.                                                      

What is claimed is:
 1. An inorganic resin composition which comprises,in combination, as component A an acidic aqueous solution of metalphosphate containing phosphoric acid, as component B an oxy-boroncompound, and as component C a wollastonite compound.
 2. The compositionaccording to claim 1, wherein the metal phosphate is selected from thegroup consisting of an aluminum phosphate, zirconium phosphate,magnesium phosphate, zinc phosphate, calcium phosphate, iron phosphate,and mixtures thereof.
 3. The composition according to claim 1, whereinsaid oxy-boron compound is selected from the group consisting of boricacid and hydrates thereof, an alkali metal and alkaline-earth metal saltof boric acid and hydrates thereof, an amine and ammonium salt of boricacid and hydrates thereof, and mixtures thereof.
 4. The compositionaccording to claim 3, wherein said oxy-boron compound is selected fromthe group consisting of boric acid and hydrates thereof, sodium borateand hydrates thereof, ammonium borate and hydrates thereof, calciumborate and hydrates thereof, and mixtures thereof.
 5. The compositionaccording to claim 3, wherein said oxy-boron compound is present in apowder or liquid form.
 6. The composition according to claim 1, whereinsaid wollastonite compound is a natural or synthetic wollastonite, incalcined or non-calcined state, or a combination thereof.
 7. Thecomposition according to claim 1, wherein said component A comprises,per 100 parts by weight of said wollastonite compound calculated on abasis of pure calcium silicate in said wollastonite compound:said metalphosphate in an amount that contains 14 to 135 parts by weight ofphosphorous pentoxide and 2 to 65 parts by weight of metal oxide.
 8. Thecomposition according to claim 7, wherein said component Acomprises:said metal phosphate in an amount that contains 24 to 86 partsby weight of phosphorous pentoxide and 5 to 47 parts by weight of metaloxide.
 9. The composition according to claim 1, wherein a water contentof the composition is from 8 to 150 parts by weight per 100 parts byweight of said wollastonite compound calculated on a basis of purecalcium silicate in said wollastonite compound.
 10. The compositionaccording to claim 9, wherein the water content is from 11 to 95 partsby weight.
 11. The composition according to claim 1, wherein saidoxy-boron compound is present, calculated on an anhydrous basis, in anamount of 0.2 to 50 parts by weight per 100 parts by weight of saidwollastonite compound calculated on a basis of pure calcium silicate insaid wollastonite compound.
 12. The composition according to claim 11,wherein said oxy-boron compound, calculated on an anhydrous basis, ispresent in an amount of 2 to 20 parts by weight.
 13. The compositionaccording to claim 6, wherein a particle size and an aspect ratio of thewollastonite are not larger than 150 μm and 10 respectively.
 14. Thecomposition according to claim 1, which further comprises an additiveselected from the group consisting of fibres, a filler, a foaming agent,a surfactant, a pigment, and a combination thereof.
 15. The compositionaccording to claim 14, wherein said surfactant is zinc stearate.
 16. Thecomposition according to claim 14, wherein said foaming agent is acarbonate, in a powder form or in an aqueous solution, selected from thegroup consisting of calcium carbonate, magnesium carbonate, sodiumcarbonate, potassium carbonate, and a combination thereof.
 17. Thecomposition according to claim 14, wherein said filler is silica or aderivative thereof.
 18. The composition according to claim 14, whereinsaid additive is a fibre selected from the group consisting of metalfibre, organic fibre, and non-metal inorganic fibre.
 19. The compositionaccording to claim 1, in the form of a cured shape.
 20. The compositionof claim 18 in the form of a cured, prepreg shape.
 21. The compositionof claim 18, wherein the fibre is glass fibre.
 22. The composition ofclaim 20, wherein the fibre is glass fibre.
 23. A process for preparingan inorganic resin composition in the form of a cured shape, saidcomposition comprising, in combination, as component A an acidic aqueoussolution of metal phosphate containing phosphoric acid, as component Ban oxy-boron compound, and as component C a wollastonite compound, whichprocess comprises:mixing said acidic aqueous solution of metal phosphatewith said oxy-boron compound at a temperature and for a time sufficientto form a further aqueous solution, contacting said wollastonitecompound with the further aqueous solution to form a slurry, andapplying said slurry on a surface, wherein said slurry sets to the formof the cured shape of the inorganic resin composition.
 24. The processaccording to claim 23, which further comprises maintaining said slurryat a temperature sufficiently low to retard a setting reaction beforebeing brought on said surface.
 25. The process according to claim 23,wherein said surface comprises a fibre mat made of fibres selected fromthe group consisting of inorganic, organic and/or metallic fibres. 26.The process according to claim 25, whereby applying the slurry on saidfibre mat effects impregnating said fibre mat with said slurry, wherebysaid slurry sets to the form of a cured, fibre reinforced shape.
 27. Theprocess according to claim 23, wherein said surface is comprised ofmetal, organic, or inorganic material.
 28. A process for preparing aninorganic resin composition in the form of a cured, prepreg shape, whichcomposition comprises, in combination, as component A an acidic aqueoussolution of metal phosphate containing phosphoric acid, as component Ban oxy-boron compound, and as component C a wollastonite compound, andwhich composition further comprises a fibre selected from the groupconsisting of metal fibre, organic fibre, and non-metal inorganic fibre,which process comprises:mixing said component A, said component B, saidcomponent C to form a slurry, impregnating fibres with said slurry toform a prepreg, maintaining said prepreg at a temperature sufficientlylow to prevent curing thereof, and applying said prepreg on a surfacethat supports said prepreg, wherein the slurry in said fibres sets tothe form of the cured, prepreg shape.
 29. A method of using an inorganicresin composition comprising incorporating said composition as a binderinto a coating or surfacing agent, said composition comprising incombination, as component A an acidic aqueous solution of metalphosphate containing phosphoric acid, as component B an oxy-boroncompound, and as component C a wollastonite compound.
 30. A method ofusing an inorganic resin composition, which composition comprises, incombination, as component A an acidic aqueous solution of metalphosphate containing phosphoric acid, as component B an oxy-boroncompound, and as component C a wollastonite compound, and whichcomposition further comprises a fibre selected from the group consistingof metal fibre, organic fibre, and non-metal inorganic fibre, saidmethod comprising incorporating said cured prepreg shape into a coatingor surfacing agent.
 31. The method of claim 30, wherein the shaped formhas a foamed structure.